Method of making patterns for propeller-blades.



R. A. PATRICK.

METHOD OF MAKING PATTERNS FOR PROPELLER BLADES.

APPLICATION FILED JAN. 11. I917.

Patented Jan. 22, 1918.

2 SHEETS-SHEET I.

R. A. PATRICK. METHOD. OF MAKING PATTERNS FOR PROPELLER BLADES.

APPL!CAT|0N FILED JAN-11 1191].

Patented Jan. 22, 1918.

2 SHEETS-SHEET 2.

Law

ROBERTA. PATRICK, OF FREEPORT, NEW YORK, ASSIGNOR TO COLUMBIAN BRONZE CORPORATION, OF FREEPORT, NEW YORK, A CORPORATION OF NEW YORK.

METHOD OF MAKING PATTERNS FOR PROPELLER-BLADES.

Specification of Letters Patent.

Patented Jan. 22', 1918;

Application filed January 11, 1917. Serial No. 141,781.

To all whom it may concern 7 Be it known that 1, ROBERT A. PATRICK, a subject of the King of Great Britaimand a citizen of Canada, residing at Freeport, county of Nassau, and State of New York, have invented certain new and useful Improvements in Methods of Making Patterns for Propeller-Blades, of which the following is a specification.

This invention relates to processes of making patterns of propellers or propeller blades for use in molding propellers.

The principal objects of the invention are to render the process of makingpatterns of the class set forth more expeditious and less expensive, and to produce blade patterns having an accurate helicoidal surface.

It is well understood that a screw pro peller is most eflicient when the face of the blade is a true screw, that'is, when the face of the blade is so generated that'it is ,an exact helicoidal plane.

In the drawings, illustrating the preferred manner of'practising the process, Figure l is a plan view of the apparatus employed in carrying out the process, the swinging pitchgenerating member being removed;

Fig. 2. a side elevation, with the swinging pitch-generating member removed;

Fig. 3 a detail side elevation of the swinging pitch-generating member;

Fig. at a side elevation showing the apparatus ready for use;

Fig. 5 a detail plan view of one of the adjustable supports for the track;

' Fig. 6 a detail side elevation of one of the adjustable supports;

Fig. 7 a detail view showing the manner of securing the pitch-generating blade to-its supports; 7

Fig. 8 a detail perspective view of a partially' finished master pattern or base; and- Fig. 9 a longitudinal sectional view of a finished pattern.

' The apparatusshown intheaccompany:

ing drawings is not claimed in this application, as said apparatus, constitutes. .the subject matter of my co-pendi'ng:application Serial No. 139,697. filed December. 29th,.

1916 ,'and allowed June 22nd,'1917."

In carrying out the improved pr'oces s, master patterns, preferably formedfwith. a ubr tern or base is tested from time to time during the shaping operation to determine the pitch of the partially shaped blade and locate the portions of the surface that do notconform to the desired pitch.

To test the blade of the stock pattern or base and ascertain the extent to which portions of the blade surface thereof must be raised or lowered by the bending and hammering operations, I prefer to employ the apparatus shown in the accompanying drawings. I

Referring to the various parts by numerals, the base of the apparatus comprises a hub or pivot portion 1 from which extends a plurality of radial arms 2, 3, 4.- and 5, of equal length, the outer ends of which are connectedby an arc shaped bar 6. The arms 2, 5 and 6 are-of-suchlength as to form a quadrant of a circle having the hub 1 asan axis- FiXed-in a socket in the hub 1 is a verti-' cally extending pivot post 7. Vertically extending posts 8, 9 and 10 are mounted at the points of intersection of arms 3. 4 and 5 with the arc-shaped bar 6. The posts 8, 9 and 10 are preferably rectangular in cross section,

and are fixed in sockets formedat the points of intersection ofthe arms, or otherwise rig.- idly affixed to the base.

Said posts 8, 9 andlO'are preferably of different heights, post 10 being the highest, post 7 9 being substantially two-thirds the height of post 10, and post 8 being one-third the height of post-10. The posts-8, 9 and 10 are preferably provided'with graduations not shownon one side thereof, post 10 beingprefer-ably graduated in inches andfractions thereof. The scale of the graduations on post 9 is preferably two-thirds of the scale of the graduations on post 10, and the scale of the graduations on post 8 is preferably one-third of the scale of graduations on post 10. A slide 11 is mounted on each post 8, 9 and 10, and said slides are provided with clamping screws 12 for securing the slides in their adjusted positions on the posts. A lever 13 is pivotally mounted, intermediate its ends, on the inner side of each slide 11, as shown at 1-1 in Figs. 5 and 6. The lever 13 is provided with a clamping jaw 15 at its upper end, and with a laterally extending arm or lug 16 at its lower end. A spring 17 normally forces the upper end of lever 13 and the clamping jaw 15 away from the slide 11. A screw 18 threaded through a laterally projecting lug 19 adjacent the lower end of the slide, is adapted to bear against lug 16 on the lever and force the clamping aw 15 against the inner wall of the slide.

A curved track 20, preferably formed of spring steel, is pivotally connected, at one end, with a short post or projection 21 at the intersection of arms 2 and 6, by a horizontal pivot pin or bolt 22. The opposite end of the track or guide 20 is free and'extends a suitable distance beyond post 10. It will be obvious that by adjusting slides 11 proportionately on posts 8, 9 and 10, and clamping said track to the slides by means of the jaws 15, with the lower edge of the track resting on pins 33, projecting from the slides 11, a track having any desired degree of pitch within the capacity of the apparatus may be formed. The upper edge of the track pro jects above the top of the slides. as shown in Fig. 6. The proper adjustment of the slides on the intermediate posts 8 and 9 is facilitated by providing said posts with graduations on a scale proportionate to the distance between said posts and the end posts 10 and 21, as heretofore described. It is obvious that, when the slides 11 are properly adjusted to the corresponding graduations on posts 8, 9 and 10, and track 20 is securely clamped so that it rests on the pins 33, the upper and lower edges of track 20 being parallel, the upper edge will form an exact portion of a helix or screw thread.

The partially formed propeller pattern 37 is supported on the base with the post 7 passing through the hub thereof, and the blade portion extending over the base with its lower forward edge adjacent arm 2 of the base, as shown in Fig. 4. Suitable spacing washers 34 are dropped on post 7 to build up a supportflfor the propeller hub suitable for the particular pattern being formed.

The vertically slidable and laterally swinging pitch-generating member is then mounted on the post 7 vabove the pattern.

The-swinging generating member comprises a hub 23 slidably and rotatably mounted on post 7, and a horizontal arm 24, secured at its inner end to said hub 23 and adapted to be swung back and forth with the shaft 7 as,

a pivot. The hub 231s provided with a suitable handle 35. Intermediate the ends of the arm 24 said arm is provided withverti- The rods 25 are independently adjustable vertically, through the arm 24, and are secured in their adjusted positions by means of clamping bolts 26. The lower ends of the rods 25' areivertically slotted at 25 as shown in F i 7 and a work-en a iiw )latej27 is 23 7 b b b clamped in said slots by means'of bolts 28 extending through said rods and through slots 29 in the blade or plate 27. The pivotal connections between the plate 27 and rods 25. permit adjustment of the rods to hold the plate or blade in an inclined position, and the slots 29 permit lateral adj ustment of the blade. A vertical rod 30 is adjustably held in an aperture adjacent the free outer end of arm 24, by means of a clamping bolt 31. A horizontally disposed grooved roller 32 is mounted at the lower end of rod 30 and adapted to engage and run upon the upper edge of the curved inclined track 20 when the work-engaging plate 27 is moved across the blade surface of a pattern having a pitch corresponding to the extending over the quadrantal base with the higher edge of the blade adjacent post 10 and the lower edge extending toward post 21. The swinging pitch-generating member is then mounted on the post with the plate 27 preferably engaging the higheredge of the blade portion of the pattern, and the pitch-generating member swung about its pivot to cause the plate 27 to ride down the inclined face of the blade pattern. If the pattern has the proper pitch the roller 32 will engage the track and plate 27 will engage the surface of the pattern throughout the movement of the generating member over the pattern. If plate 27 engages a portion of the pattern surface having too low a pitch, the roller. is lifted from the track and thereby indicates that the pitch is insuflicient, and the degree of such insuflicieney,

and .if theplate 27 failstoengage the pat-' tern surface it indicates that the pitch is ex cessive, and the degree of excess. It is obvious, that the upper surface of track 20, which is a true helix, serves as a master to guide the-arm 24 through the grooved roller 82, so that plate 27 in itsmovement across the face of the blade portion of the attern, will generate an exact helicoidal sur ace.

The independent adjustment of rods 25 permits the plate 27 to be adjusted to an inclined position for use in connection with blade patterns having a lateral inclination or dip. The longitudinal adjustment of plate 2? permits adjustment of the plate when used in connection with patterns having hubs of different diameters.

When the pliant stock pattern or base has been shaped to closely approximate the desired form, that portion of the surface thereof corresponding to the working face of the blade is coated with plaster-of-Paris, or other suitable plastic material, as indicated at 38. lVhile the plastic coating 38 is still soft, the pattern is again placed in the apparatus heretofore described, and the swinging pitch-generating member moved across the surface thereof. The plate 27 serves as a scraper and removes all the surplus mate rial of the plastic coating 38. A smooth and true helicoidal surface is thus generated 011 the blade portion of the pattern. The pattern is then allowed toset until the plastic coating hardens; or the coating may be hardened by baking, or in any other suitable manner. After the coating has hardened I prefer to further smooth the surface thereof by sand-papering or otherwise. Both surfaces of the pattern may be coated and treated as above described, if desired.

Instead of scraping the plastic surface of the pattern while still soft, the coating 38 may be allowed to harden in the first instance, and the surface then finished by filing, sand-papering, bufiing, or the like, until an accurate and smooth helicoidal surface of the desired pitch is generated. The surface of the pattern, during the finishing operation inst described, is tested from time to time in the same manner as the malleable base or master pattern is tested during the shaping thereof.

What I claim is:

1. The process of making propeller patterns consisting in manipulating a pliant base until it approximates the desired configuration, coating one side of said base with plastic material, and removing the surplus portions of the coating to shape the pattern to the desired form.

2. The process of making propeller patterns consisting in manipulating a pliant metallic base until it approximates the desired configuration, coating one face of the blade portion of the base with plastic material, removing the surplus portions of'said coating while still plastic to shapethepattern to the desired form, and subsequently allowing the plasticcoating to harden.

3. The process of making propeller patterns consisting in manipulating a pliant metallic base until it approximates the desired configuration, coating one face of the blade portion of the base with plastic material, removing the surplusportions of said coating while still plastic to shape the pattern to the desired form, allowing the coating to harden, and subsequently smoothing the surface of the hardened coating.

4:. The process of making propeller patterns consisting in coating a master pattern approximating the desired configuration with plastic material and removing the surplus plastic material to produce a pattern having the desired configuration.

5. The process of making propeller patterns consisting in coating a master pattern approximating the desired configuration with plastic material, removing the surplus portions of said coating while still plastic to shape the pattern to the desired form, and subsequently hardening said coating.

6. The process of making propeller patterns consisting in coating a master pattern approximating the desired configuration with plastic material, allowing said coating to harden, and removing the surplus portions of said hardened coating to shape the pattern to the desired form.

7. The process of generating the blade portions of propeller patterns, consisting in shaping a pliant metallic master pattern by manipulation until the blade portion thereof approximates the desired pitch, coating one face of the blade portion with a non-metallic material in a plastic state, manipulating said plastic coating to produce a smooth surface having the desired pitch, and subsequently allowing the coating to set and harden.

8. The process of making propeller blade patterns consisting in coating a base approximating the desired. conformation with a non-metallic composition in a plastic state,

shaping the coated base while the coating 18 still plastic by a sweep controlled by a master helix having the desired pitch, and subsequently allowing the coating to harden.

9. The process of making propeller patterns consisting in coating one surface of the blade portion of a stock pattern approximating the desired conformation with a plastic material, and subsequently generating a blade surface having the desired pitch by removing the surplus plastic material with a generator controlled by a master helix.

10. The process of making propeller patterns cons sting in shaping a stock pattern to approximately the conformation desired, coating said shaped stock pattern with a plastic material, and subsequently removing surplus coating material and smoothing the coated surface of the pattern to generate a blade surface having the desired conformation by agenerating element controlled by v a master helix.

' 11. The process of making propeller patterns consisting in shaping a blank of stock to approximately the conformation desired,

coating a portion of said shaped blank with a plastic material and subsequently Working the surface of said coated portion to the desired contour by a generating element controlled by a master helix.

In testimony whereof I hereunto aifix my signature.

ROBERT A. PATRICK.

Copies ofi this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

7 Washington, D. C. 

